The US forces in Syria have bombed a militia group fighting alongside the Syrian government forces in southern Syria on Thursday, the US-led coalition has confirmed.
UPDATE: US-led airstrikes on Syrian military hit tank & construction equipment, casualties likely
The coalition said in a statement that the Syrian forces "posed a threat" to US and partner troops at Tanf base near the Syria-Iraq-Jordan border.
"This action was taken after apparent Russian attempts to dissuade Syrian pro-regime movement south towards At Tanf were unsuccessful, a coalition aircraft show of force, and the firing of warning shots," the statement said.
Having commented on the incident, the US Defense Secretary James Mattis said Washington was not deepening its role in the Syrian conflict, but would defend its troops.
The Syrian forces allegedly entered a so-called "de-confliction" zone in the Homs Governorate, which was perceived as a threat to "US-allied troops." The militia forces allegedly clashed with the Pentagon-backed Maghawir Al-Thawra militant group (formerly known as New Syrian Army), which called in coalition air support.
“We notified the coalition that we were being attacked by the Syrian army and Iranians in this point and the coalition came and destroyed the advancing convoy," Reuters cited a militant representative as saying.
US special forces have been present in the area "for many months" to train and advise Free Syrian Army fighters. Damascus considers such Washington's presence illegal in the country, as no official invitation has been extended to the US to conduct any military action on its territory.
A tank and a bulldozer were hit during the strike, AP reports, citing unnamed US defense officials. There have been unconfirmed reports of casualties on the Syrian side.
READ MORE: US denies responsibility for Deir ez-Zor airstrikes that killed dozens
According to Al-Masdar News citing the Syrian military, the coalition warplane entered Syrian airspace from the Jordanian border. It reportedly hit a convoy of five tanks, destroying two of them.
Six military personnel were killed and another three injured, Al-Masdar News reported, citing the military.
The attack does not reflect an escalation in Syria, an unnamed senior US defense official told Fox News, claiming that "there is no change in policy" on Washington's side.
The attacked paramilitary group affiliated with the Syrian army has been given no warning ahead of the strike "in contradiction to what we've heard from the US sources," political commentator from Damascus, Alaa Ibrahim told RT, citing military sources in Syria.
"The area where the attack took place has been a scene of a hectic race between the Syrian army and groups affiliated with it and rebel groups backed by the US-led coalition. There have been reports that the US and Britain are preparing for some kind of land incursion," Ibrahim said.
The de-escalation or safe zones agreement in Syria came into effect earlier this month, set up as a temporary measure for six months with the possibility of extending them for another half a year.
The zones were established in several Syrian provinces, including in Homs, as agreed by the guarantor states – Russia, Iran and Turkey – during negotiations in the Kazakh capital of Astana, where all parties expressed hope that the initiative will lead the way to end the conflict in Syria.
READ MORE: Trump-Lavrov meeting focused on Syria safe zones & need to expand them nationwide
The issue of establishing and expanding the de-escalation zones dominated discussions between Russian Foreign Minister Sergey Lavrov and US President Donald Trump at the White House last week. "At the center of our conversation was the initiative which President Trump voiced at an early stage of his presidency, namely the creation of security zones or zones of de-escalation, in which there will be no fighting, except against the terrorists, who need to be expelled from there," Lavrov said.